Motorcycle chain guard

ABSTRACT

An oil splash cover for a motorcycle which comprises an elongated U-shaped upper housing section and a similarly configured inverted lower housing section spaced from each other along most of their lengths by brackets, and brought together and bolted at their trailing ends. The forward ends of the thus-held housing sections rest upon motorcycle frame members and the brackets securing the upper and lower housing sections in their spaced relationship are looped and fitted around a swinging arm for the cycle&#39;&#39;s rear wheel to support the housing in relation to said arm. A chain guide is mounted at a forward position to guide a broken end of the chain around a front sprocket. The two housing sections are configured along their edges adjacent the rear wheel axle to provide a larger opening. The lower housing section is further orificed to receive the end of an oiler tube and to locate said end above the lower portion of the chain loop to drip oil on the chain. The tube extends upwardly to an oil reservoir disposed below the motorcycle seat or on top chain cover, the reservoir being provided with a manual valve means to regulate the oil drips through the tube and onto the chain. An oil drip drain is also provided at the trailing end of the rear section.

United States Patent 1191 Wood 11 1 3,724,582 1 Apr. 3, 1973 [54]MOTORCYCLE CHAIN GUARD [76] Inventor: George R. Wood, 528 East Fairview,Inglewood, Calif. 90302 221 Filed: Oct. 18, 1971 [21] Appl.No.: 190,252

Primary Examinerl(enneth H. Betts Attorney-William l-l. Pavitt, Jr. eta1.

[57] ABSTRACT An oil splash cover for a motorcycle which comprises anelongated U-shaped upper housing section and a similarly configuredinverted lower housing section spaced from each other along most oftheir lengths by brackets, and brought together and bolted at theirtrailing ends. The forward ends of the thus-held housing sections restupon motorcycle frame members and the brackets securing the upper andlower housing sections in their spaced relationship are looped andfitted around a swinging arm for the cycle s rear wheel to support thehousing in relation to said arm. A chain guide is mounted at a forwardposition to guide a broken end of the chain around a front sprocket. Thetwo housing sections are configured along their edges adjacent the rearwheel axle to provide a larger opening. The lower housing section isfurther orificed to receive the end of an oiler tube and to locate saidendabove the lower portion of the chain loop to drip oil on the chain.The tube extends upwardly to an oil reservoir disposed below themotorcycle seat or on top chain cover, the reservoir being provided witha manual valve means to regulate the oil drips through the tube and ontothe chainfAn oil drip drain is also provided at the trailing end of therear section.

3 Claims, 3 Drawing Figures 1 I MOTORCYCLE CHAIN GUARD BACKGROUND OFTHIS INVENTION clothes of the cyclist. Nor have prior art guards been effective to inhibit the accumulation of sand, dirt or other grit whichtends to cause wear on the chain. As a result, chain life is usuallyfigured by the cyclist to be about 6,000 miles. Efforts to increase thischain life by regular cleaning and lubrication of his cycle chainusually result in the cyclist finding oil thrown up on his clothing.

In addition, prior art chain guards or covers have been largelyineffective in preventing aruptured chain from damaging the adjacentmotorcycle wheel or even preventing it from flying up to injure thecyclist. At high speeds, chain rupture represents'a real hazard. Thus,the high-speed cyclist should ordinarily look to replacing his drivechain not much after, 5,000 miles of driving in order to be safe.

. Where prior art chain guards or covers have sought to provide a fairlycomplete covering of the moving chain, they have made it difficult forthe cyclist to lubricate the chain and regularly to check the conditionof the chain. Also, chains will tend to run hot in such closed chainhousings. Prolonged operation of the motorcycle at high speeds canproduce great elevation of the temperature of the chain and therebyincrease the danger of its rupture through metal fatigue.

Another problem with prior art chain guards or covers is their tendencyto interfere with other parts of the motorcycle such as the chaintensioner and frame members.

SUMMARY OF THE INVENTION The present invention obviates all of theproblems encountered with prior art chain guards or covers byconstructing the chain guard of a pair of U-shaped housings which extendfrom a motorcycle frame member below the seat and upon which framemember the forward ends may be supported, to a point rearwardly of therear wheel chain sprocket and any tensioner which may extend afttherefrom. The two housings aligned with their respective edges opposedto each other, but are spaced apart in parallel relationship andmaintained in such relationship by brackets secured to their respectivesides and looped over one of the swing arms whichsupport the rear axleof the motorcycle to be supported by such arm. Axially adjacent the rearwheel chain sprocket, the edges. of the U- shaped housings areconfigured to provide a curved and greater opening between therespective edges. One of the housings is orificed and provided with aremovable orificed plate through which the end of an oiler tube may bepassed to drip oil onto the chain. The

' other end of. the tube is connected to valving means from an oilreservoir located beneath the motorcycle seat. The trailing ends of thehousings desirably maybe bolted together.

While a chain guard or cover so constructed provides an almost closedhousing, there is suff cient air spacing I invention is, however,adequate to keep out much of the sand, dirt and other grit which tendsto get into the chain where it is not shielded. Moreover, provision ismade for continuous periodic lubrication of the chain while at the sametime the lubrication is prevented from being thrown up onto the clothesof the cyclist.

As a consequence of these features of a chain guard constructed inaccordance with the present invention, chain life should besubstantially increased to almost double what may be expected of chainswith or without presently available chain guards. Moreover, the chainguard of the present invention does not interfere with the other partsof the motorcycle and may be constructed to sell at a reasonable andacceptable price.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a. perspective view of achain guard mounted on the rear end of a motorcycle. 7 FIG. 2 is a sideelevation of the chain guard shown in FIG. 1.

FIG. 3 is a section taken of the line 33 of FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Refering to the drawings, thechain guard of the present invention is constructed of a pair ofU-shaped upper and lower housing 10, 12, each of which extend rearwardlyfrom cross-frame members l4, 16 to a point aft of the rear motorcyclesprocket 18 and the chain tensioner 20. The forward end 10a of the upperhousing desirably rests on and is supported by the crossframe member 14and the forward end 12a of the lower housing 12 may rest upon and besupported by the midstand bolt 16. The upper and lower housings 10, 12are maintained in spaced parallel relation to each other by brackets 22,24, which extend between and are secured to a side 10b,.12b, of each ofthe housings 10, 12, respectively. As may best be seen in FIG. 3, eachbracket 22, 24 is looped outwardly and circularly to fit around theswinging arm 26 which extends from the frame swivel 28 rearwardly tosupport the rear wheel axle 30. The bracket 22, 24 may be secured to thehousing sides 10b, 12b by bolts or screws 32. The after portions of thehousings 10, 12 are configured axially opposite the axle 30 toprovide acurved open area 34 and the trailing ends 10c, 12c of the housings l0,12, respectively, are preferably brought together and molded to providea registering terminal projection 36 through which a screw 38 may bepassed in order to secure the two ends 10c, 12:: together. i

In order to provide lubrication for the chain a reservoir in the form ofan inverted bottle 40 may be attached by a claim 42 to the seat framesupport 44. This bottle reservoir 40 may be capped by a manual pullvalve 46 the outlet of which is connected to a flexible tube 48. Thetube 48 extends downwardly to the inlet end 50 of a spigot 52 whichpasses through an eliptical plate 54 removably secured to cover asimilarly configured opening 56 in the side 12b of the lower housing 12.The discharging nozzle 57 of the spigot 52 is directed downwardly and isdirectly over the chain 58 in its lower course around the sprockets 18and 60.

A chain guide 61 is mounted at a forward position on the upper housingand extends around the chain 58 and the sprocket 60. If the chainbreaks, the guide 61 prevents the broken end of the chain 58 fromwhipping forward and breaking the transmission case. The broken end isguided around the sprocket 60 to be deposited in the cover.

in use the housing 10 may be slipped in between the rear shock absorber62 and the wheel 64 and located so that its forward end rests upon thecross-frame member 14. The lower housing member 12 may then be broughtup from below and secured to the upper housing 10 by screwing thebrackets 22 and 24 into the sides 10b and 12b of the housings 10, 12. Atthis time, the brackets spaced parallel relation to each other and arelargely supported by the swing arm 26. The forward end 12a of thehousing 12 is also disposed to be supported by the midstand bolt 16. Inaddition, the trailing ends of the housings l0, 12 are secured byinserting the screw 38 into theorificed terminal projection 36 andtightening it down.

The eliptical plate 54 with the spigot 52 may then be placed over theorifice 56 and secured by the bolts or screws 53. The tube 48 may beattached to the inlet end of the spigot 52 and connected to the outletof the valve 46 which caps the inverted bottle reservoir 40. By pullingthe valve cock 47 the operator of the motorcycle may regulate the amountof lubricant which passes from the reservoir into the tube 48 and thencethrough the spigot 52 to drip onto the chain 58. The amount of lubricantwhich most desirably should be passed onto the chain is normally afunction of the speed at which the motorcycle is being operated and thetime during which such speed is continued. In the event that theoperator should desire to check the condition of the motorcycles chain58, he may simply remove the eliptical plate 54 from the side 12b of thelower housing 12 and feel the condition of the chain with hisfingers. Inthe event that there is excess oil on the chain it will normally bedropped into the lower rear area 12d of the hower housing 12 and willpass out through the flexible drain tube 66. However, even if excessivelubricant should be dripped on the chain 58 it will be found that thecofiguration of the housing will permit the chain from throwing up anyoil on the clothes of the cyclist. On the other hand, while the chain isthus adequately shielded, the spacing between the opposite edges of thehousings 10, 12 is such, particularly when coupled with the curved openarea 34, as to quite adequately ventilate the chain 58 when working onthe sprockets 18 and 60 to prevent overheating. The particular chainguard shown in the drawing is one which is adapted specifically for aHonda 750 motorcycle, but the principles of construction of such ahousing may readily be applied to providing chain guards for most othertypes of motorcycles.

I claim: 1. A motorcycle chain guard for a motorcycle including a framewith a lower midframe cross member, an engine and a rear wheel mountedon an axle extending between the rear ends of a pair of swing arms anddriven by a chain extending between a first sprocket on the engine driveshaft and a second sprocket on said rear wheel, said chain guardcomprising:

A. An upper U-shaped elongated shell extending from the motorcycleslower midframe cross member to a point beyond the rear wheel chainsprocket and any chain tensioner extending rearwardly therefrom;

B. A lower U-shaped elongated shell of similar extent to that of theupper shell;

C. A plurality of bracket means, each said means being secured betweenone side of the said upper shell and a side of the said lower shell tosecure said shells in opposed parallel spaced relationship to each otherabout the exposed portion of the motorcycle chain which extends rearwardfrom the engine to the second sprocket, said bracket means adjacent theswinging arm being closely looped about said arm to provide some supportfor the two thus-secured shells therefrom;

D. The forward ends of said thus-secured shells resting upon a crossframe member for further support therefrom, and said shells beingsecured together at their trailing ends;

E. Said shells being configured along their adjacent edges axiallyopposite the rear wheel axle to provide a greater ventilating spacingabout the sprocket;

F. An oil reservoir mounted beneath the motorcycle seat, said reservoirincluding a tube extending downwardly therefrom and controllable valvemeans to regulate the quantity of the oil which is passed from thereservoir into said tube;

G. One of said shells having a removable plate, said plate beingorificed to pass therethrough the lower end of said tube and to disposethe same to drip oil upon the chain; and v H. The lower shell beingorificed in its lowermost rear area to vent oil accumulated thereinrearwardly thereform.

2. The chain guard as described in claim 1, wherein a venting tubeextends rearwardly from said orifice in said lowermost rear area of thelower shell.

3. The chain guard as described in claim 1, wherein the rear ends of thesaid shells are brought together, are threadedly orificed in registryand secured to each other by screws.

1. A motorcycle chain guard for a motorcycle including a frame with alower midframe cross member, an engine and a rear wheel mounted on anaxle extending between the rear ends of a pair of swing arms and drivenby a chain extending between a first sprocket on the engine drive shaftand a second sprockEt on said rear wheel, said chain guard comprising:A. An upper U-shaped elongated shell extending from the motorcycle''slower midframe cross member to a point beyond the rear wheel chainsprocket and any chain tensioner extending rearwardly therefrom; B. Alower U-shaped elongated shell of similar extent to that of the uppershell; C. A plurality of bracket means, each said means being securedbetween one side of the said upper shell and a side of the said lowershell to secure said shells in opposed parallel spaced relationship toeach other about the exposed portion of the motorcycle chain whichextends rearward from the engine to the second sprocket, said bracketmeans adjacent the swinging arm being closely looped about said arm toprovide some support for the two thus-secured shells therefrom; D. Theforward ends of said thus-secured shells resting upon a cross framemember for further support therefrom, and said shells being securedtogether at their trailing ends; E. Said shells being configured alongtheir adjacent edges axially opposite the rear wheel axle to provide agreater ventilating spacing about the sprocket; F. An oil reservoirmounted beneath the motorcycle seat, said reservoir including a tubeextending downwardly therefrom and controllable valve means to regulatethe quantity of the oil which is passed from the reservoir into saidtube; G. One of said shells having a removable plate, said plate beingorificed to pass therethrough the lower end of said tube and to disposethe same to drip oil upon the chain; and H. The lower shell beingorificed in its lowermost rear area to vent oil accumulated thereinrearwardly thereform.
 2. The chain guard as described in claim 1,wherein a venting tube extends rearwardly from said orifice in saidlowermost rear area of the lower shell.
 3. The chain guard as describedin claim 1, wherein the rear ends of the said shells are broughttogether, are threadedly orificed in registry and secured to each otherby screws.